A basic requirement in determining the health of a human adult or neonate is to measure certain vital sign parameters, such as blood pressure, pulse rate, blood oxygen saturation, and respiratory rate. For example, measuring blood pressure in a human adult is typically accomplished using either an oscillometric-based method or an auscultatory method, both of which traditionally involve the application of an inflatable blood pressure cuff around the arm of the subject. While oscillometric-based and auscultatory methods are easily implemented with a human adult, these methods are not well suited for subjects such as neonates due to their diminutive size and inability to comprehend and cooperate with the procedure.
Beyond the inability to accurately monitor vital sign parameters in a small subject, traditional methods of measuring vital sign parameters are generally carried out on a periodic basis, as opposed to providing near-continuous monitoring. This is because traditional methods of monitoring generally required that the subject be disturbed in some manner. For example, in monitoring blood pressure, blood flow through the subject's body member was occluded, through inflation of the blood pressure cuff, in order to measure blood pressure. Inflation of the blood pressure cuff may be disturbing to a neonate, particularly during their rest if performed on a periodic basis.
Accordingly, a need exists for apparatuses and methods for monitoring vital sign parameters, such as blood pressure, oxygen saturation, pulse rate, and respiration, regardless of whether the subject is a human adult, a neonate or some other biological entity. The apparatuses and methods should be easily implemented and obtain accurate results, as well as be carried out in a near-continuous manner so as to allow for monitoring without disturbing the subject. Also, the apparatuses and methods should be employed such that any biological entity, regardless of size, may be monitored.